Regional Landscape Ecosystems of Michigan, Minnesota, and Wisconsin
SUBSECTION II.1. Upper Minnesota River Country
DISCUSSION: Subsection consists of a 30-mile-wide area of calcareous ground moraine, located on both sides of the Minnesota River. It was originally vegetated with tallgrass prairie. The ground moraine was deposited by the Des Moines lobe (Hobbs and Goebel 1982). The Minnesota River occupies a broad channel created by Glacial River Warren, which drained Glacial Lake Agassiz. Two areas of silt- and clay-rich lacustrine deposits are located in the northwestern and southeastern parts; these areas contain large, unbroken areas of poorly drained soils (Cummins and Grigal 1981). Steep topography is restricted to the Big Stone moraine area at the extreme western edge of the subsection, to the sides of the river, and to the sides of abandoned river channels.
Sub-subsections: None.
ELEVATION: 750 to 1,300 feet (229 to 396 m).
AREA: 12,103 square miles (31,347 sq km).
STATES: Minnesota.
CLIMATE: Typical continental climate with extremes in temperature from summer to winter (Hargrave 1992). Annual precipitation ranges from 25 inches in the west to 30 inches in the east, with 11 to 13 inches of growing season precipitation. As in Section I, approximately 11 percent of the annual precipitation falls from November through February (Wendland et al. 1992), probably resulting in extreme desiccation of most woody plants and contributing to the dominance by prairie grasses. Growing season length is approximately 147 to 152 days.
BEDROCK GEOLOGY: Bedrock is covered with 100 to 400 feet of glacial drift for most of the subsection (Olsen and Mossler 1982). Most of the subsection is underlain by Cretaceous shale, sandstone, and clay; the extreme eastern edge is underlain by more resistant Ordovician dolomite (Morey 1976). This resistant dolomite also underlies the irregular topography of the Southern Oak Plains subsection (III.4) to the east. There is a major area of exposed granite bedrock scoured by Glacial River Warren near Ortonville, and also in the river valley just west of Morton (Wheeler et al. 1992a). Sporadic exposures of Sioux quartzite of the upper Precambrian occur in northeastern Cottonwood County and southwestern Brown County in the southeast (Morey 1981, Olsen and Mossler 1982).
LANDFORMS: Loamy ground moraine (till plain) is the predominant landform, but end moraine, outwash deposits, and sand and clay lake plains are also present. The ground moraine is relatively flat, but contains many more small lakes and ponds (potholes) than Glacial Lake Agassiz. The steepest topography of the subsection is the Big Stone moraine, which has both steep kames and broad slopes. There are also steep bluffs along the Minnesota River Valley.
LAKES AND STREAMS: More than 150 lakes are larger than 160 acres (University of Minnesota et al. 1969, 1979, 1981a). Major rivers include the Minnesota and Chippewa.
SOILS: Most of the soils are loams formed from calcareous glacial drift. Although some soils are clayey, and sandy and gravelly soils occur locally, these account for only a small percentage of the subsection (University of Minnesota et al. 1969, 1979, 1981a). Cummins and Grigal (1981) show most of the division as Udoll and Aquolls on relatively level topography, generally with 15 feet or less of local relief; dry prairie soils (primarily Ustolls) also occur on relatively level topography. A Minnesota Department of Natural Resources map of "probable original wetlands" shows a large percentage of poorly drained or wet mineral soils, but these soils are broken into much smaller topographic units than the soils of the Red River Valley as a result of the more dissected topography of the ground moraine.
PRESETTLEMENT VEGETATION: The presettlement vegetation of the division was primarily tallgrass prairie, with many islands of wet prairie (Kratz and Jensen 1983, Marschner 1974). Flood-plain forest of silver maple, elm, cottonwood, and willow occurred along the Minnesota River and other streams. On portions of the Big Stone moraine, both steep kames and the broad slopes along the coulees supported dry and dry-mesic prairie (Wheeler et al. 1992a). There were also dry gravel prairies on kames.
NATURAL DISTURBANCE: Fire was responsible for maintaining the prairie. Fire suppression has allowed woodlands to develop from what were originally oak openings or brush prairies (Wheeler et al. 1992a).
PRESENT VEGETATION AND LAND USE: Subsection is the heart of the Minnesota Cornbelt (Wright 1972). Wheeler et al. (1992b) found upland prairie species to be common throughout most of the subsection (based on herbarium records).
RARE PLANT COMMUNITIES: Prairies and associated wetlands that once dominated the subsection are all rare now; these include dry prairie, mesic prairie, wet prairie, glacial till prairie, and calcareous seepage fens. Gravel prairies persist on the steep hills associated with the Minnesota River and the Big Stone moraine. The outcrops of Morton gneiss and Sioux quartzite support diverse "rock specialists" and species of temporary pools. Significant calcareous fens occur in the central portion of the Minnesota River Valley, supporting species such as Rhynchospora capillacea (beak-rush), Scleria verticillata (nut-rush), and Cladium mariscoides (twig-rush).
RARE PLANTS: The drier portions of the subsection, such as the Big Stone moraine, commonly support Astragalus missouriensis (Missouri milk-vetch), Astragalus flexuosus (slender milk-vetch), Solidago mollis (soft goldenrod), and Happlopappus spinulosus (cutleaf ironplant). Fire-protected xeric habitat among granite outcrops (along the Minnesota River) support the cactuses, Coryphantha vivipera (ball cactus) and Opuntia macrorhiza (plains prickly pear). Lespedeza leptostachya (prairie bush clover) persists on mesic to dry hill prairies associated with quartzite outcrops and with the Morton gneiss and on gravel prairies associated with abandoned channels of the Glacial River Warren. Several prairie plants are found only in the wetter prairies at the eastern edge of the subsection, including Asclepias sullivantii (Sullivant's milkweed), Cacalia plantaginea (tuberous indian-plantain), Eryngium yuccifolium (rattlesnake-master), and Parthenium integrifolium (wild quinine). Other rare species include: Buchloe dactyloides (buffalo grass), Cypripedium candidum (small white lady's-slipper), Mammillaria vivipara (ball cactus), Myosurus minimus (mousetail), Schedonnardus paniculus (tumblegrass).
RARE ANIMALS: Birds: Athene cunicularia (burrowing owl), Bartramia longicauda (upland sandpiper), Lanius ludovicianus (loggerhead shrike), Limosa fedoa (marbled godwit), Speotyto cunicularia (burrowing owl); Insects: Hesperia dacotae (Dakota skipper), Oarisma poweshiek (Powesheik skipper); Arthropods: Phidippus pius (jumping spider); Reptiles: Eumeces fasciatus (five-lined skink); Fish: Scaphirhynchus platorynchus (shovelnose sturgeon).
NATURAL AREAS: State Natural Areas: Blue Devil Valley, Bonanza Prairie, Clinton Prairie, Cottonwood River Prairie, Gneiss Outcrops, Osmundson Prairie; The Nature Conservancy Preserves: Plover Prairie, Clinton Prairie, Schaefer Prairie, Chippewa Prairie, Kasota Prairie, North Heron Lake Preserve, Red Rock Prairie; Others: Alexandria Moraine Prairies (three areas identified as critical landscapes for biodiversity protection), Big Stone Prairie Potholes, Florida Creek Slough, Glacial River Warren, Jeffers Petroglyph Historic Site, Liable Woods, Ottawa Bluffs, Plover Prairie, Staffanson Prairie, University of Minnesota-Morris, Wahpeton Prairie, Yellow Bank Hills Scientific and Natural Area, Salt Lake Wildlife Management Area.
PUBLIC LAND MANAGERS: Wildlife Management Areas: Bashaw, Cedar Rock, Florida Creek, Foley, Gollnick, Indian Lake, Kemen, Kibler, Lac Qui Parle, Little, Minneopa, Ottawa, Perch Creek, Prairie, Ras-Lynn, Salt Lake, Sena, Swan Lake, Thielke Lake, Vallers, Victory, Vogel, Walnut Lake, Walter, Watline, West Toqua, White Prairie; Waterfowl Production Areas: Barry Lake, Bomsta, Colbert, Eids Lutheran, Farrell, Florida Creek, Haseman, Hastad, Hegland, Helgesen, Hillman, Historical Society, Krogsrud, Landers, Pearson, Prairie, Redhead Marsh, Rothi, Tangen, Taylor, Twin Lakes, Williams; State Parks: Big Stone Lake, Flandrau, Upper Sioux Agency; Others: Cottonwood County Park, Eagle Nest County Park, Renville County Park #2, Seven Mile Creek County Park, Skalbakken County Park, Granite Falls Memorial Park, Big Stone National Wildlife Refuge.
CONSERVATION CONCERNS:
BOUNDARIES: The subsection could be further subdivided, separating out parts (primarily till plain or lake plain) with different drainage conditions, soil textures, or slope classes that resulted in vegetation differences. This would require further research because intensive agricultural land use has destroyed original patterns of drainage and vegetation.
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| Figure 9.—Subsection II.1: Big Stone moraine, Traverse County, Minnesota. The steep side slopes of Glacial River Warren, seen in this photo, and limited areas of steep kettle-kame topography are among the only unfarmed portions of this subsection. Dry-mesic and dry prairie dominate the slopes. The woodlands in the background, which were much less extensive before settlement are the result of fire exclusion. Most of the gently rolling moraines of this subsection are intesively farmed. Minnesota Department of Natural Resources photo by R. Dana. |
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| Figure 10.—Subsection II.1: Outcrops of granitic bedrock in the Minnesota River Valley near Ortonville, Minnesota, provide a fire-protected, dry habitat which supports cactus species. Heavy grazing in surrounding prairie has allowed exotic grasses to become the dominant vegetation. Minnesota Department of Natural Resources photo by R. Dana. |
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